Chronic kidney disease (CKD) patients often have high levels of a substance called fibroblast growth factor-23 (FGF-23), a phosphorus excreting hormone, which has been related to heart disease. As kidney function declines, less phosphorus is removed by the kidneys and as a result phosphorus accumulates in the blood. In response to elevated phosphorus levels, more FGF-23 is released to help facilitate the excretion of extra phosphorus into the urine. In addition to effects on FGF-23, increased phosphorus levels can lead to calcification (hardening) of the blood vessels in the CKD population.

Phosphate binding medicines are used in CKD patients to lower the amount of phosphorus absorbed by the stomach and intestines after eating meals and snacks. In patients with CKD, studies have shown that phosphate binders can lower FGF-23 levels in the blood. Lowering FGF-23 levels in CKD patients may also lower substances in the blood that cause calcification of blood vessels in the CKD population.

This study is being done to determine if using phosphate binders, either sevelamer carbonate or calcium acetate, in the earlier stages kidney disease (before dialysis) can decrease FGF-23 and biomarkers (substances in the blood) associated with hardening of the blood vessels and heart disease.

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Please refer to this study by its ClinicalTrials.gov identifier: NCT01277497